A 79-year-old man presented with a fall and vomiting. The finding of significant postural hypotension associated with severe hypotonic hyponatraemia (Na 114 mmol/L, Osmolarity 244 mmol/L) mandated a Short Synacthen Test (cortisol 98 mmol/L at baseline and 238 mmol/L 30-minute post synacthen) and ACTH (6 ng/L) which confirmed central hypoadrenalism. This led to revelation of multiple pituitary axes involvement: hypogonadism (testosterone 1.1 nmol/L, FSH 1.3 U/L, LH 1.1U/L), growth hormone deficiency (IGF-1: 5 nmol/L), and partial central diabetes insipidus confirmed on a water deprivation test. The prolactin and thyroid test were normal. Confrontation visual field test was unremarkable. The MRI pituitary then revealed a normal pituitary gland with thickened stalk up to 5 mm. A discussion at pituitary multidisciplinary meeting (MDT) raised suspicion for lymphocytic hypophysitis and led to IgG4 level measurement, which was markedly elevated at 12.7 g/L (0-1.3 g/L). Granulomatous infiltration was less likely in this context especially with normal calcium and ACE level. A screening for systemic IgG4 disease with CT thorax and abdomen revealed multiple hilar and mediastinal lymphadenopathy, measuring up to 1.3 cm. These findings were stable on serial imaging which precluded bronchoscopy.
On this ground, a diagnosis of IgG4 related hypophysitis was entertained. In the absence of sight-threatening radiological findings or debilitating symptoms such as headache, high dose steroid was not required as the condition was deemed to be indolent. Patients symptoms responded to physiological hydrocortisone and testosterone replacement and remained so for the subsequent 3 years of follow-up. Serial annual MRI pituitary consecutively showed non-progressive findings.
Discussion: While acute hypophysitis presenting with florid symptoms or ophthamological involvement may require high dose steroid, this case presented as indolent burn-out disease was safely managed with mere hormonal replacement with no evident progression in the 3 year of follow-up. Histological confirmation may not be possible or even meaningful in these settings.